"You keep staring at me, I'm gonna get a complex," Dean said.
Sam blinked a little to clear his eyes, unaware he'd locked his eyes on Dean. It was better than staring at the mile markers (26 to the state line, Montana this time) or the maps or the journal. Dean never changed the way he drove, left knee leaned against the door like it made a difference that the hum of the engine and road could be felt in his bones; left hand at 12 o'clock on the wheel, right tapping out a rhythm on his thigh.
"I'll drive," Sam said.
"Uh uh," Dean said immediately. "You've got the stares, and I don't wanna have to try and keep you awake. If you're bored, then talk about something."
Sam cocked his head back and gave him a concerned look. "Talk, as in make sounds with my mouth? Because I don't remember you ever being a fan of hearing me talk."
"See, because stuff like that is almost always what comes out of you," Dean said without glancing at him. "Snarky little bastard."
Sam laughed under his breath. "Can't win with you," he said. "Okay. Today's the 50 year anniversary of the interstate system."
"Trivia," Dean muttered. "I get trivia from him."
"Hey, your idea," Sam said. "You gonna shut up and listen?"
"There is no 'or what'," Sam said. "It sounded like a question but mostly it's what you're gonna do."
Dean shook his head and rolled his eyes.
"FDR ordered it after he saw a similar road system in Germany," Sam said. "It was for evacuation and military purposes. So stuff could be moved fast, in case of nuclear attack."
"Lucky us," Dean said. "Instead it just gets used for vacationers and shipping."
"True or false," Sam said. "One out of every five miles on an interstate is straight so it can be used for a landing strip in an emergency."
Sam watched his brother's eyes dart along the road ahead, checking the sides and the next mile marker. Calculating in his head, running the last few miles over in his mind. Weighing Sam's tone of voice, checking his eyes. Dean would always do that, take in all the available information in just a moment or so and decide what to do with it before most people knew there was even information to work with at all.
"Good idea," Dean said. "He got the idea from the Germans, right? During wartime? It'd make sense. But it's bullshit. I'd have noticed that a long time ago."
Sam grinned. "Yeah, it's just an urban legend."
Dean smirked. "Wanna play truth or dare?"
"No, Dean," Sam said, face falling into a scowl. Not after the thing with the flagpole. Or the mailbox. Or the ducks.